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Human Body Systems
Chapter 35-1 of Biology. Organization of the Body The levels of organization in a eukaryote include cells, tissues, organs, and organ systems. Tissues are groups of similar cells that perform a specific function in the body (like connecting a muscle to a bone). An organ is a group of tissues that work together to acomplish a specific task or function, like sight. An organ system is a group of organs that perform similar functions. 'Cells' The basic unit of structure and function in a living thing. Specialized cells are particulary suited to perform a cetain function. 'Tissues' A tissue is a group of cells that perform a single function. There are four different type of tissues: epithelial, connective, nervous, and muscle. *Epithelial tissue includes glands and tissues that cover interior/exterior body surfaces. *Connective tissue provides support for the body and connects its parts. *Nervous tissue transmits nerve impulses throughout the body. *Muscle tissue enables the body to move. 'Organs' A group of differnet types of tissues (as listed above) that work as a team to do a specific function. The eye, for example, is made up of all four kinds of tissues that work together to achieve one purpose - sight. Organ Systems Organ systems are a group of organs that peform similar functions. For example, the brain (part of the nervous system) gathers information from the outside world and coordinates the body's responses. There are 11 organ systems in all. 'Nervous System' Consisting of the brain, spinal chord, and peripheral nerves, the nervous system's job is to recognize and coordinate the body's response to changes in internal and external enviroments. 'Integumentary System' Made up of your skin, hair, nails, sweat and oil glands, this system serves as a barrier between infection and injury as well as helping to maintain your body temperature. It also provides protections against ultraviolet radation from the sun. 'Respiratory System' Contains the nose, pharnyx, larnyx, trachea, bronchi, bronchioles, and lungs and provides oxygen needed for celluar respiration. It also removes excess carbon dixode from the body. 'Digestive System' The digestive system sports the mouth, pharynx, esophagus, stomach, small and large intestines, as well as the rectum. Its main function is to convert food into simpler, smaller molecules that can be used by cells in the body. It also eliminates wastes from the body. 'Excertory System' Contains the skin, lungs, kidneys, ureters, urinary bladder, and the urethra. Its job is to elimiate waste products from the body, but in a way that still maintains homeostatis. 'Skeletal System ' Sports the bones, cartilage, ligaments, and tendons while supporting the body and protecting internal organs. The system also allows movement, stores mineral reserves, and provides a place for blood cell formation. 'Muscular System' Includes the skeletal muscle, smooth muscle, and cardiac muscle. It works with the skeletal system to produce voluntary movement, circulate blood, and help move food through the digestive system. 'Circulatory System' Contains the heart, blood vessals, and of course, blood. The system primarly serves to bring oxygen, nutrients, and hormones to cells; fight infection; remove cell waste; to help regulate body temperature. 'Endocrine System' Holds the hypothalamus pituary, thyroid, parathyroids, adernals, pancreas, and the ovaries in females or testes in males. The system serves to control both growth, development, and the metabolism as well as to help maintain homeostatsis. 'Reproductive System' Includes the testes, penis, epididymis, vas deferens, and urthera in males and the ovaries, Fallopian tubes, uterus, and vagina in females. The system produces reproductive cells and helps nuture and protect a baby in females. 'Lymphatic/Immune System' Contains white blood cells, thymus, spleen, lymph nodes and vessels. Helps protect the body from diease and collects the fluid lost from blood vessels and returns it to the cicrculatory system. Maintaining Homeostasis Homeostatis is the process which organisms keep internal conditions the same even if there are changes in the external enviroments. It is maintained in the body by feedback loops. 'Non-Living Example' In most houses, heat is given by a furnace. When the temperature in a home rises above the point designated by the thermostat, the thermostat turns the furnace off. Such systems are said to be controlled by feedback inhibition, a process where a stimules produces a response that opposes the original response. Systems controlled by feedback inhibition are generally very stable and fully automated. 'In the Body' Maintenace of homeostatis requires the intergration of all organ systems at all times. If the nerve cells sense that the core temperature has dramatically dropped bellow 37 degrees C, the hypothalmus produces chemicals that singal cells throughout the body to speed up their activities. Head produced by this increase causes a gradual rise in body temperature, which is picked up by the hypothalmus, which slows down cells to keep body temperature from rising to a dangerous level. This minimizes the production of heat and is why you feel tired on a hot day. Category:Biology, Homeostasis, Cells, Organs, Tissues, Organ Systems